Method and apparatus for producing fibrous tubular articles

ABSTRACT

METHOD AND APPARATUS FOR PRODUCING TUBULAR ARTICLES FORMED OF FIBROUS MATERIAL WHEREIN A MOVING MAT OF FIBROUS MATERIAL IS WRAPPED ABOUT A MANDREL ROTATING ABOUT AN AXIS MOVING ALONG THE PATH OF THE MAT. THE MAT IS THEN WRAPPED AROUND THE MANDREL UNTIL A DESIRED QUANTITY OF FIBROUS MATERIAL IS ACHEIVED. THEREAFTER, THE MAT AND MANDREL ARE CONVEYED TO A SIZING STATION WHERE THE OUTER DIAMETER AND CONFIGURATION OF THE TUBULAR ARTICLE ARE FINALLY SET.

Jan. 1,: 1974 R. D. TERRY METHOD AND APPARATUS PRODUCING FIBROUS TUBULALR ARTICLES (5 Sheets-Sheet 1 Original Filed May 2'7, 1970 INVENTOR. I RUPERT D. TERRY ATTORNEY R. D. TERRY Jan. 1, 1974 METHOD AND APPARATUS PRODUCING FIBROUS TU BULALR ARTICLES Original Filed May 2'7, 1970 5 Sheets-Sheet FIG. 2

7 INVENTOR. RUPERT D. TERRY ATTORNEY FIG.4

Jan. 1, 1974 TERRY 3,783,069

METHOD AND APPARATUS PRODUCING FIBROUS TUBULALR ARTICLES Original Filed May 27, 1970 i 5 Sheecs-Sheet .5

INVENTOR. RUPERT D. TERRY Wm FIG- gLA ATTORNEY United States Patent 3,783,069 METHOD AND APPARATUS FOR PRODUCING FIBROUS TUBULAR ARTICLES Rupert Douglas Terry, Toledo, Ohio, assignor to Johns- Manville Corporation, New York, N .Y. Continuation of abandoned application Ser. No. 41,018, May 27, 1970. This application Mar. 3, 1972, Ser. No.

Int. c1. B6511 81/02 U.S. 156-184 24 Claims ABSTRACT OF THE DISCLOSURE This is a continuation of application Ser. No. 41,018, filed May 27, 1970, now abandoned.

BACKGROUND OF THE INVENTION It has heretofore been proposed to form a tubular article of fibrous material by wrapping a mat of resin impregnated fibrous material on a mandrel and thereafter curing the resin binder by moving a series of mandrels from a wrapping station to a heating station, or by removing the tubular articles from the mandrel after wrapping, and then placing the articles in an oven. Also, it has been proposed to effect the binder curing operation at the same station as the Wrapping wherein the fibrous material remained on the mandrel upon which it was initially wrapped.

In the prior art methods and apparatus for forming tubular articles of mats of fibrous material, the mandrels about which the fibrous mat is wrapped are positively driven, and adapted to rotate about fixed axes.

In each of the prior art apparatus, the operating procedures involved means for indexing the mandrels which necessarily required the braking, clutching, and driving techniques.

The present method and apparatus involves the production of tubular articles of fibrous material wherein the mandrels employed are not positively rotated, but rather the fibrous material is driven, causing the same to form around the mandrel which, in turn, is moved longitudinally along the path of travel of fibrous material.

Illustrations of the prior art are found in United States Letters Patent: No. 2,331,146, Slayter; No. 2,674,557, Boggs; No. 3,446,684, Pall.

SUMMARY The present invention relates to a method of and apparatus for the continuous production of tubular articles formed of fibrous material.

Among the objectives of the invention is to produce tubular articles formed of fibrous material wherein the articles are produced in a continuous fashion, eliminating any necessity of handling the articles during the intermediate production steps and thereby eliminating any of the discontinuous intermediate operations.

Another object of the invention is to produce tubular articles formed of fibrous material wherein the method and apparatus arranged in accordance with the invention provide for increased production of such articles than has been practical heretofore.

3,783,069 Patented Jan. 1, 1974 ice A further object of the invention is to provide a method and apparatus for the production of tubular articles of fibrous materials of a wide variety of sizes, both in respect of inside diameter, as well as to the thickness of the tubular wall, and the density of the media.

In one of its broader aspects, the invention contemplates the production of tubular articles from a mat of mineral fibers which comprises the steps of: advancing a mat of mineral fibers along a path; rolling the mat on a mandrel rotatable about an axis traveling along the path of the mat, normal to the direction of advancement of the mat and at a speed less than the speed of advancement of the mat; conveying the rolled mat and mandrel between a pair of oppositely rotating members to roll an additional length of mat on the mandrel to produce a tubular article having the desired quantity of mineral fibers; and, passing the tubular article to a sizing station to produce a final outer dimension thereto.

Another feature of the invention involves the use of divergently spaced conveying surfaces moving in opposite directions at slightly different speeds selected to cause the mandrel to advance in the direction of the divergence in coordination with the build-up of the wall thickness and the outer diameter.

BRIEF DESCRIPTION OF THE DRAWINGS Other objects and advantages of the invention \m'll become readily apparent to those skilled in the art from reading the following detailed description of an embodiment of the invention when considered in the light of the accompanying drawings, in which:

FIG. 1 is a perspective view of apparatus containing the structural concepts of the invention for continuously producing tubular articles from a mat of fibrous material;

FIG. 2 is an enlarged fragmentary side view of the leading end portion of a mat of fibrous material spaced from the mandrel upon which it is to be wrapped;

FIG. 3 is an enlarged fragmentary side view similar to FIG. 2 showing the leading end portion of the fibrous mat wrapped around the mandrel;

FIG. 4 is an enlarged fragmentary side view of the secondary rolling station of the apparatus illustrated in FIG. 1;

FIG. 5 is an enlarged fragmentary side view of the sizing station of the apparatus illustrated in FIG. 1; and

FIG. 6 is an enlarged fragmentary side view of the final heating station of the apparatus illustrated in FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT With general reference to the drawings, there is illustrated an apparatus particularly adaptable for producing tubular articles of fibrous material, which articles are useful as pipe insulation, for example. Referring to FIG. 1 of the drawings, there is illustrated a system for continuously producing tubular articles made from fibrous material, typically resin bonded glass fiber mat 10. The mat 10 is formed in any of the conventional manners wherein the fibers of glass are formed, coated or impregnated with a suitable resin, such as phenol formaldehyde, for example, and blown onto a moving conveyor, such as the endless conveyor 12 formed of a woven wire and driven in the direction indicated by the arrow. The mat 10 is typically formed of fibers of glass which are disposed in random fashion in a plane substantially parallel to the plane of the conveyor 12. The mat 10 is further typically cut into discrete lengths determined by the diameter, wall thickness, or desired density of the finished product, as will become clearly manifest hereinafter.

At the entry of the apparatus illustrated in FIG. 1, there is disposed a conveyor 14, which is arranged generally normally to the path of travel of the conveyor 12. The conveyor 14 includes a main frame 16 on the outer end of which is located a drive motor 18 that drives a sprocket 20. The sprocket 20, in turn, drives a chain member 22, which is guided about a pair of spaced apart idler sprockets 24 and 26.

Discrete lengths of mandrels 28 are disposed on the chain member 22, which moves the mandrels transversely over the conveyor 12 and thence automatically discharges the same when the mandrel 28 is in the desired position over the conveyor 12. At the discharge point, the mandrels 28 are caused to roll over an inclined heated surface 30, which effectively heats at least the outer peripheral surface of the mandrels 28, and thence come to rest in a supply zone 32. The supply zone 32 is equipped with a gating mechanism which effectively meters the discharge of the heated mandrels 28 onto the conveyor 12. The heated mandrels 28 are mounted to be discharged onto the conveyor 12 so as to be positioned immediately in front of the leading edge of the mat of the resin bonded fiber glass material, as illustrated in FIG. 2.

The gate mechanism for releasing the heated mandrels 28 on to the conveyor 12 is typically energized by a photocell sensing circuit which photoelectrically senses the presence of the leading edge of a length of mat 10 and thereupon effectively releases a single one of the mandrels 28 from the supply zone 32 to fall onto the surface of the conveyor 12.

It must be understood that the mandrels 28 are heated to effectively cause the binder material in the mat 10 to adhere to the outer peripheral surface of the mandrels 28. Alternate techniques could be employed to effect the desired adherence, such as to coat the mandrels 28 with an adhesive substance which could be rendered tacky upon the application of heat or be sprayed with a catalyst, for example, to bring about the desired chemical reaction.

The conveyor 12 thereafter moves both the mat 10 and the heated mandrel 28 until the mandrel 28 contacts the gate arms 34, at least a pair of which is disposed in spaced relation across the conveyor 12 (FIGS. 2 and 3). The gate arms 34 effectively bring about an alignment of the mandrel 28, causing the same to assume a position which is perpendicular or normal to the path of travel of the mat 10 and the conveyor 12. Manifestly, only the outer ends of the heated mandrels 28 are contacted by the gate arms 34, which temporarily impede the forward movement of the mandrels 28 on the conveyor 12. However, since the conveyor 12 continues to advance, such advancing movement will simultaneously cause the mandrels 28 to rotate about its axis and properly align with the mat and conveyor.

With the forward movement of the mandrel 28 being impeded, the leading edge of the mat 10 continues to move forward and contacts the rotating heated mandrel 28. At this point, the leading edge of the mat 10 adheres to the mandrel 28 and is caused to be rolled or wrapped upon the mandrel 28, as illustrated in FIG. 3. Due to the fact that the mat 10 is typically comprised of fibers of glass containing an uncured binder substance, the heat of the mandrel 28 initiates the curing of the binder, causing the same to become tacky and thereby readily adhere to the outer peripheral surface of the mandrel 28.

It will be noted that on the terminal end of each of the arms 34, there is disposed a microswitch 36. The microswitch 36 may be connected in a series circuit which is energized only upon physical contact of both switches, indicating that the mandrel 28 is properly aligned. Upon energization of the switches 36, a timing circuit is energized, which is set to time out in a desired time interval necessary to build up the desired thickness of the mat 10 on the mandrel 28. It has been found that satisfactory results are achieved by effecting two wraps or thicknesses of the mat 10 on the mandrel 28, at which time the gate arms 34 are raised or swung out of contact with the ends of the mandrel 28, permitting the already rolled mat and mandrel to advance to the next winding or roll-up station, generally indicated by reference numeral 40, and specifically illustrated in FIG. 4.

The roll-up station 40 consists of a pair of spaced apart, upstanding, substantially vertically extending columns 42, supported at their lower ends by a transversely extending base member 44. Since the structure on each of the sides is identical, only a single side structure will be described in detail. At each of the base member 44, and at the upper end of the upright member 42, there are disposed roller members about which a continuous woven wire belt or chain 46 is supportingly mounted. To enable the tautness of the belt 46 to be varied, the roller disposed at the upper end of the upstanding column 42 is mounted in an adjusting mechanism consisting of a rack 48 and an associated pinion 50.

The ends of the base member 44 of the above assembly may be raised and lowered together, or relative to one another, by the provision of adjusting screws 52 and 54. A control wheel 56 is adapted to move the screw 52 up and down relative to the member 44, while a control wheel 58 is adapted to move the screw 54. It will be appreciated that similar screw members located on the other side of the conveyor 14 may be suitable coupled to the above referred to screws by drive chains, so that actuation can be simultaneously effected by actuation of the respective control wheels 56 and 58.

The woven wire belt or chain 46 is typically driven through a drive sprocket 60 which, in turn, drives one of the rollers which support the chain 46. The chain 46 is driven in a direction opposite to that of the conveyor 12, and thereby effects a complete roll-up of the mat 10 onto the mandrel 28. It will be noted that the lowermost run of the chain 46 is disposed such that the exit end 62 is spaced further from the surface of the conveyor 12 than the spacing at the inlet end 64, to produce a divergence of the conveying surfaces from the inlet end to the exit end. Such relative disposition permits the complete roll-up of the mat 10 onto the mandrel 28 and effectively applies substantially the same compressing forces on the tubular elements being formed.

It will be appreciated that the speed of travel of the mat 10 and the mandrel 28 through the roll-up station 40 is determined by the relative speed of the chain 46 and the conveyor 12. Further, it will be appreciated that the relative spacing between the chain 46 and the conveyor 12 is determined by the thickness of the mat, outside diameter of the mandrel 28, and the number of wraps of the mat 10 on the mandrel 28.

Upon exit from the roll-up station 40, the completely wrapped or wound assembly of the mat 10 and mandrel 28 is caused to be conveyed to a sizing station 70, illustrated in particularity in FIG. 5. The function of the sizing station is typically to compare the wound assembly to the desired outside diameter. The structure of the sizing station 70 is similar to the roll-up station 40, and, more particularly, consists of a pair of spaced apart, upstanding, substantially vertically extending columns 72, supported at their lower ends by a transversely extending base member 74. Since the structure of each of the sides of the sizing station 70 is substantially identical, only a single one will be described in detail. At each end of, the base member 74, and at the upper end of the upright member 72, there are disposed roller members about which a continuous woven wire belt or chain 76 is supportingly mounted. To enable the tautness of the belt or chain 76 to be varied, the roller disposed at the upper end of the upstanding column 72 is mounted in an adjusting mechanism consisting of a rack 78 and an associated pinion 80.

The inlet end 81 and the exit end 83 of each side of the above described sizing station assembly '70 may be raised and lowered together by the provision of adjusting screws 82 and 84. A control wheel 86 is adapated to move the adjusting screws 82 and 84 up and down relative to the member 74. It will be noted that the single control wheel ,86 is coupled through a typical chain drive to. .the..adjusting screw 82, which, in ,turn, is coupled through another chain drive to the adjusting screw 84, to effect the desired simultaneous movement. It willbe appreciated that the similar screw members located on the other side of the conveyor 12 are likewise suitably coupled to the chain actuated by the control wheel 88 so that actuation can be simultaneously effectedto raise and lower the entire assembly relative to the conveyor 12. i g

The woven wire belt or chain 76 is driven through a drive sprocket 90 which, in turn, drives one of the rollers which drivingly support the chain 76. The chain 76 is driven ina direction opposite to that of "the conveyor 12'. Assuming that the chain 76 is driven at a speed equal to one half of the speed of the conveyor 12, the articles comprised of the rolled mat and the mandrel 28 will rotate in a counter-clockwise direction, as viewed in FIG. 5, and will travel in the direction of the movemer t of the conveyor 12 at a speed equal to one quarter} of the speed of the conveyor 12.

The distance or spacing between the conveyor 12 and thelower surface orrun of the chain 76 determines the outside diameter of the tubular articles being formed. As'mentioned before, the mat is, in the preferred embodi rnent, comprised of glass fibers impregnated with a, binder material such as phenol formaldehyde resin, which is in its uncured stage. Since the resin is uncured, the sizing station 70 can, in addition to determining the outside diameter of the tubular articles being formed, determine the density of the fibrous medium constituting the tubular walls.

Upon exit from the sizing station 70, the sized tubular assembly is caused to be conveyed to a curing station 96, illustrated in particularity in FIG. 6. The function ofthe curing station 96 is to cure the resin, at least in the regions of "the outer peripheral surface of the formed articles, to elfectivelys'et and maintain the outer dimension thereof. This objective is achieved by a heated plate 98 spaced vertically from theconveyor 12a distance substantially equal to the predetermined outside diameter of the tubular articles being'formed. The heated plate 98 may be heated by various means and, in the preferred embodiment, the use of an electric resistant heating element' is preferred. It will be appreciated that the vertical spacing between the lower surface of the plate 98 and the conveyor 12 may be varied by adjusting means of theltype' illustrated in respect of the apparatus shown in FIGS. 4 and 5, or other adjusting means.

While the curing" station 96 has been mentioned as being. employed only to' cure the binder content-in the outer region of the tubular articles being formed, which typically can'be achieved by only a single revolution of the article, it-will be appreciated that the curing station 96 could be varied to allow for the curing o fthe entire binder content of the article.

In the preferred embodiment, as the tubular article leaves the curing station 96, only the outer skin of the article and the innerskin, adjacent the mandrel 28 are cured. The remaining portion of the binder is cured by manually. transporting theformed articles to another station which would include suitable heating means. As a general rule, before entering this final heating means, the mandrels 28 are removed from the tubular articles. It has been found that such procedure is readily accomplished without any deformation or attrition of the inner, surface thereof.

In conclusion, the apparatus illustrated and described above provides a method for continuously forming tubular articles of fibrous material without the need for any discontinuous intermediate steps. Also, the apparatus may be utilized for producing tubular articles of different dimensions regarding inside diameter, outside diameter, Wall thickness, and density. The length of the tubular articles is determined by the width of the mat 10 being used. The wall thickness is determined by the thickness of mat 10; the length of the discrete lengths of mat 10; or the degree of compression achieved between the lower runs of the chains 46 and 76 and the conveyor 12; or combinations of the above.

In accordance with the provisions of the patent statutes,

I have explained the principle and mode of operation of my invention and have illustrated and described what I now consider to represent its best embodiment. However, 'I desired to have it understood that the invention may be practiced otherwise than as specifically illustrated and described without departing from its spirit or scope I claim:

1. Apparatus for producing tubular articles from mats of fibrous material comprising:

(a) a conveyor for advancing a mat of fibrous material along a path;

(b) means for disposing a mandrel across said conveyor and normal to the direction of advancement of the mat;

(c) means for causing a leading portion of the mat to adhere to the mandrel;

(d) means at a first winding station for rolling at least one turn of the leading end portion of said mat onto said mandrel; and

(e) a diverging conveying surface at a second winding station farther along the path, said diverging conveying surface being disposed in spaced relation above said conveyor and moving in a direction opposite to said conveyor at a speed less than the speed of said conveyor to effectively roll said mat on said mandrel to form a tubular article as the mat and mandrel are advanced in the direction of divergence.

2. Apparatus as defined in claim 1 wherein said means for causing a leading portion of the mat to adhere to the mandrel is a means for heating the mandrel prior to the disposition of the mandrel across the conveyor and Wherein said means for disposing a mandrel on said conveyor includes a second conveyor disposed substantially normal to the direction of travel of said first mentioned conveyor.

3. Apparatus as defined in claim 1 wherein said means for causing a leading portion of the mat to adhere to the mandrel includes an inclined heated surface on which said mandrel is caused to travel before being disposed on said conveyor.

4. Apparatus as defined in claim 1 wherein said means for disposing a mandrel on said conveyor includes a gating mechanism for selectively delivering a single mandrel to said conveyor.

5. Apparatus as defined in claim 1 wherein said means for rolling the leading end portion of said mat on said mandrel includes a gating mechanism for selectively impeding the advancement of said mandrel on said conveyor.

6. Apparatus as defined in claim 5 wherein said gating mechanism includes a pair of laterally spaced arms positioned to contact opposite end portions of said mandrels.

7. Apparatus as defined in claim 6 including means for selectively moving said arms out of contact with said mandrel.

8. Apparatus as defined in claim 1 including a conveying surface disposed in spaced relation above said conveyor moving in a direction opposite to said conveyor at a speed less than the speed of said conveyor to effectively determine the outside diameter of the tubular article formed by cooperative relation of said conveyor and said diverging conveying surface as the tubular article is advanced between the conveying surface and the conveyor.

9. Apparatus as defined in claim 8 including a heated zone through which said tubular article is passed.

10. Apparatus as defined in claim 9 wherein said heated zone includes a heated plate disposed in spaced relation above said conveyor.

11. A method of producing tubular articles from a mat of fibrous material comprising:

(a) advancing a length of mat of fibrous material along a path;

(b) locating a mandrel across the path and normal to the direction of advancement of the mat;

(c) adhering a leading end portion of the mat to the mandrel;

(d) rolling at least one turn of the leading end portion of the mat onto the mandrel at a first winding station by rotating the mandrel about an axis normal to the direction of advancement of the mat;

(e) conveying the mat and mandrel with the mat partially rolled onto the mandrel farther along the path to a second winding station;

(f) locating the leading end portion of the mat and the mandrel between a pair of diverging conveying surfaces with the mat in contact with the diverging conveying surfaces; and

(g) rolling a remainder of the mat onto the mandrel while advancing the mat and mandrel along the path by moving the diverging conveying surfaces in opposite directions at slightly different speeds selected to cause the mat and mandrel to advance in the direction of divergence in coordination with the buildup of the wall thickness and the outer diameter of the tubular article as the remainder of the mat is rolled thereon.

12. The method as defined in claim 11 wherein said fibrous material is comprised of mineral fibers.

13. The method as defined in claim 12 wherein said mineral fibers are glass.

14. The method as defined in claim 13 wherein the fibrous material is impregnated with an uncured binder.

15. The method as defined in claim 14 wherein said binder is a thermosetting compound.

16. The method as defined in claim 14 including the step of heating the mandrel before the mat is rolled thereon whereby heat from the mandrel causes the binder in the leading portion of the mat to become tacky and the mat is adhered to the mandrel.

17. The method as defined in claim 14 including the final step of curing the binder.

18. A method of producing tubular articles from a mat of fibrous material, comprising:

(a) advancing the mat of fibrous material along a path;

(b) locating a mandrel across the path and normal to the direction of advancement of the mat;

(c) rolling at least one turn of the leading end portion of the mat onto the mandrel at a first station by rotating the mandrel about an axis normal to the direction of advancement of the mat;

(d) conveying the mat and mandrel, with the mat partially rolled onto the mandrel, farther along the path to a second winding station;

(e) locating the leading end portion of the mat and the mandrel between a pair of diverging conveying surfaces with the mat in contact with the diverging conveying surfaces;

(f) rolling a remainder of the mat onto the mandrel while advancing the mat and mandrel along the path by moving the diverging conveying surfaces in opposite directions at slightly different speeds selected to cause the mat and mandrel to advance in the direction of divergence as the mat is rolled on the mandrel to produce a tubular article having the desired quantity of fibrous material; and

(g) advancing the tubular article farther along the path to a sizing station to produce a final outer dimension thereto.

19. The method as defined in claim 18 wherein the fibrous material is impregnated with an uncured binder.

20. The method as defined in claim 19 wherein said binder is a therrnosetting compound.

21. The method as defined in claim 19 including the step of heating the mandrel prior to rolling the mat thereon whereby heat from the mandrel causes the binder in the leading portion of the mat to become tacky and the mat is adhered to the mandrel.

22. The method as defined in claim 19 including the final step of curing at least the binder in the outer peripheral zone of the tubular article being formed.

23. The method as defined in claim 18 wherein the fibrous material is mineral fibers.

24. The method as defined in claim 23 wherein said mineral fibers are glass.

References Cited UNITED STATES PATENTS 2,674,557 4/1954 Boggs 156184 2,331,146 10/1943 Slayter 156-184 3,063,887 11/1962 Labino 156184 X 2,442,948 6/1948 Bogoslowsky 93-8 R 3,347,725 10/ 1967 Stephens et al 156184 3,247,044 4/ 1966 Pechmann 156-447 X 2,621,823 12/1952 Perry 156450 X ALFRED L. LEAVITI, Primary Examiner D. A. SIMMONS, Assistant Examiner US. Cl. X.R. 

